Calculation with algae supply
Scientists have used a widespread blue-green algae to power a microprocessor continuously for a year – and counting – using nothing but ambient light and water. Their system has the potential to be a reliable and renewable way to power small electronic devices.
The system, comparable in size to an AA battery, contains a type of non-toxic algae called Continuous cyst which collects energy naturally from the sun through photosynthesis. The microscopic current generated then interacts with an aluminum electrode and is used to power a microprocessor.
“Our photosynthetic device does not run out like a battery, because it constantly uses light as an energy source.” – Chris Howe
The system is made of ordinary, cheap and mainly recyclable materials. This means that it could easily be played hundreds of thousands of times to power large numbers of small devices as part of the Internet of Things. Researchers say it may be more useful in off-grid situations or in remote locations, where small amounts of electricity can be very beneficial.
“The growing Internet of Things needs a growing amount of energy, and we believe it should come from systems that can produce energy, rather than just storing it as batteries,” said Professor Christopher Howe, of the University of Cambridge’s Department of Biochemistry. co-senior author of the work.
He added: “Our photosynthetic device does not run out like a battery, because it constantly uses light as an energy source.”
In the experiment, the device was used to power an Arm Cortex M0 +, which is a microprocessor widely used in Internet of Things devices. It operated in a home environment and semi-outdoor conditions under natural light and relative temperature fluctuations and after six months of continuous power generation the results were submitted for publication.
The study was published on May 12, 2022, in the journal Energy & Environmental Science.
“We were impressed by the stability of the system for a long time – we thought it could stop after a few weeks, but it just kept going,” he said. Paolo Bombelli at the Department of Biochemistry, University of Cambridge, his first paper author.
Seaweed does not need food, because it creates its own food as it photosynthesizes. And despite the fact that photosynthesis requires light, the device can even continue to produce energy in times of darkness. Researchers believe this is because algae process part of their food when there is no light, and this continues to generate electricity.
The Internet of Things is a huge and growing network of electronic devices – each using only a small amount of energy – that collects and shares data in real time over the Internet. Using low-cost computer chips and wireless networks, billions of devices are part of this network – from smartwatches to temperature sensors at power stations. This number is expected to increase to one trillion devices by 2035, requiring a huge number of portable power sources.
Researchers say that feeding trillions of Internet of Things devices that use lithium-ion batteries would not be practical: they would need three times more lithium than is produced worldwide each year. And traditional photovoltaic devices are made using hazardous materials that have adverse environmental effects.
The project was a collaboration between the University of Cambridge and Arm, a company that leads in microprocessor design. Arm Research developed the highly efficient Arm Cortex M0 + test chip, built the board, and created the cloud data collection interface presented in the experiments.
Reference: “Powering a microprocessor by photosynthesis” by P. Bombelli, A. Savanth, A. Scarampi, SJL Rowden, DH Green, A. Erbe, E. Årstøl, I. Jevremovic, MF Hohmann-Marriott, SP Trasatti, E. Ozer and CJ Howe, May 12, 2022, Energy & Environmental Science.
DOI: 10.1039 / D2EE00233G
The research was funded by the National Biofilms Innovation Center.